Hydrocarbon fluids, including oil and natural gas, can be obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a wellbore that penetrates the formation. Once a wellbore is drilled, the formation is tested to determine productive capacity, pressure, permeability and nature of the reservoir fluids, the extent of the reservoir in the formation, or a combination of these characteristics. This testing, which is referred as drill stem testing (DST) generally involves lowering a test string made up of a variety of components into the wellbore, hydraulically isolating a layer of interest from the rest of the well and perforating the layer using perforating guns to enable fluid to flow from the layer either into a chamber that is part of the test string or to the surface through suitable tubing. The components in the test string can include a test valve, packer, perforation guns and various sensors.
Often a formation has multiple layers of interest from which a production fluid can flow. Because the various layers traversed by the wellbore can have different characteristics, testing of such arrangements may involve isolating each layer from the others so that the characteristics of that layer can be assessed independently of the other layers. In many arrangements, testing starts at the lowest layer of the formation and sequentially moves up after each test is performed. However, sequential testing may require the test string to be removed from the wellbore so that the tested layer can then be hydraulically isolated from the higher layers. Repeatedly pulling a test string and then running it back into the well is time consuming and adds significantly to the total time needed to completely test the well. Once tested, various completion components can be installed to enable and control the production of fluids from the various layers.
Before, during and after completion of the well, including during testing of the well to determine a completion strategy, data representative of various downhole parameters, such as reservoir pressure and temperature, as well as data representative of the state of various downhole components (e.g., flow valves, test valves) are monitored and communicated to the surface. In addition, control information is communicated from the surface to various downhole components, to enable, control or modify downhole operations, such as control signals to actuate various downhole tools and to shift one or more tools from one state to another. Wired, or wireline, communication systems can be used for the communications between the surface and downhole. Wireless communication systems, such as those that use acoustic or electromagnetic transmission mediums, also can be used to exchange information between downhole components and surface systems.